Prospective blinded trial of a fecal antigen test for the detection of Helicobacter pylori infection.

Objective: We prospectively studied an FDA-approved stool test for the diagnosis of Helicobacter pylori infection based on the detection of antigens shed in stool.

Methods: We studied 108 patients undergoing endoscopy. Stool samples were collected on the day of the endoscopy and read in a blinded manner by a technician who was unaware of the findings of the endoscopy. The results of stool testing were compared to those of the rapid urease test (Pyloritek).

Results: There were 51 patients infected with H. pylori by rapid urease testing and 57 who were not. The sensitivity of the stool test was 86% (95% confidence interval: 77-96%), the specificity was 91% (81-97%), with a positive predictive value of 89% (77-96%) and a negative predictive value of 88% (81-97%). The likelihood ratio for a positive test was 10.18 and the likelihood ratio for a negative test was 0.11.

Conclusions: The stool test was sensitive and specific for the detection of H. pylori in a U.S. population.